Allows you to wrap your express async handlers in a way that removes the need to put all your function body handlers in a try catch phrase. Instead, if an error is thrown, it returns a default response from the server

wrapper.ts

import { Request, Response, NextFunction } from 'express';

type ExpressRouteFn<T> = (req: Request & Partial<T>, res: Response, next: NextFunction) => unknown;

export function wrapper<T = {}>(fn: ExpressRouteFn<T>): ExpressRouteFn<T> {
  return function(req, res, next) {
    return (fn(req, res, next) as Promise<ExpressRouteFn<T>>).catch((err) => next(err));
  }
}

export function wrapMulter<T = {}>(multerFn: ExpressRouteFn<T>): ExpressRouteFn<T> {
  return wrapper(async (req, res, next) => {
    return multerFn(req, res, function(err) {
      if(err) {
        console.error(err);
        if(err.code === 'LIMIT_FILE_SIZE') {
          return res.status(400).json({ error: 'File size too large' });
        }
        return res.status(400).json({ error: 'Invalid file' });
      }
      next();
    });
  });
}

wrappers.js

const express = require('express')

/**
 * @callback ExpressRouteFn
 * @param {express.Request} req
 * @param {express.Response} res
 * @param {Function} next
 */

/** 
 * @param {ExpressRouteFn} fn
 * @return {ExpressRouteFn}
 */
function wrapper (fn) {
  /**
   * @param {express.Request} req
   * @param {express.Response} res
   * @param {Function} next
   */
  return function(req, res, next) {
    return fn(req, res, next).catch((err) => next(err));
  }
}

/** 
 * @param {ExpressRouteFn} fn
 * @return {ExpressRouteFn}
 */
function wrapMulter(multerFn) {
  return wrapper(async (req, res, next) => {
    return multerFn(req, res, function(err) {
      if(err) {
        console.error(err);
        if(err.code === 'LIMIT_FILE_SIZE') {
          return res.status(400).json({ error: 'File size too large' });
        }
        return res.status(400).json({ error: 'Invalid file' });
      }
      next();
    });
  });
}

module.exports = {
  wrapper,
  wrapMulter,
}